Question for bullet casters

[Cypress]

I have been talking about this on the gunsmithing venue and need a little advice from all of you who have tinkered with casting bullets to better fit a bore. I slugged the barrel on my Type I Arisaka and found the grooves at .270-.271 and the lands at .257. The 6.5 Jap should shoot a .264 bullet but this one has the carcano action and it seems that the barrel was set up for the carcano round(.268). My questions are how much accuracy can be gained from going to the .268 bullet and would you have any caveats about trying the larger bullet in this gun. I think I can put the carcano expander in the jap dies so loading shouldn't be a problem. I've never played this game before so come on with the advice!!!!

 

[NuJudge]

If you have .270 grooves and are going to shoot a .268 bullet in it, expect considerable Leading. The gasses will blow by the bullet, cutting large amounts of Lead off the bullet and depositing it in the bore.

I find it best to fit the bullet to the throat..

CDD

 

[Cypress]

The bullets I intend to try are Hornady Jacketed .268 diameter made specifically for the Carcano round but I am unsure of how tight most bullets fit a bore in general and how much clearance affect accuracy and pressure. I figured the guys here that casted bullets would have a lot of knowledge in this area.

 

[243winxb]

Arisaka is Japanese(6.5 X 50mm Arisada). Carcano is Italian (6.5 X 52mm Mannlicher Carcano). Both 6.5 but very different i think. Not an expert here. Both in the Lyman 45 edition list grove diameter at .264" on there test guns. There is a NOTE: "If your groove diameter is larger than .264" , you could experience gas blow-by (gas from breech due to low pressure) when using the listed starting loads with the standard bullet size. We suggest that you wear shooting glasses when working out loads and that you consider the use of cast bullets sized to the exact groove diameter of your particular rifle" If you would use cast bullets sized to your groove diameter. Is there enough clearance in the chamber neck area to keep from crimping the round in the chamber and making high dangerous pressure??? I would make the gun a wall hanger myself. A jacketed bullet in .264" is made to fit a .264" groove diameter.

 

[243winxb]

The Bullets I intend to try are Hornady Jacketed but I am unsure of how tight most bullets fit a bore in general and how much clearance affect accuracy and pressure. I figured the guys here that casted bullets would have a lot of knowledge in this area.

Modern powders need to build pressure to burn correctly. A loose JACKETED bullet (.264") fit in an over size bore would not work in my opinion, given the grove diameter of .270" you listed. Accuracy would be very poor, bullet even might keyhole if they clear the bore at all.

 

[Jim Watson]

This isn't a benchrest rifle, about all you can do is load up some of those .268" bullets and see how they shoot in your .270" barrel. The American Theory is that the bullet should fill the grooves of the rifling. The European Theory was that there should be someplace for the jacket metal displaced by the lands to go.

The only thing to be cautious of is to be sure that a cartridge loaded with a .268" bullet will chamber FREELY. As said, a round tight in the chamber neck will develop excess pressure worse than an oversize bullet... which you don't have anyhow.

 

[243winxb]

i see you added that the jacket bullet is in diameter .268". With the lands at .257" it might work??

 

[243winxb]

http://findarticles.com/p/articles/mi_m0BQY/is_4_50/ai_113853252/pg_1 Read the 2nd page about loading data.

 

[Ed Gallop]

I learned to reduce or eliminate leading by slugging the barrel and using a lead bullet at least .001 or .002 larger than the grooves. It allows the bullet to grab the grooves instead of sliding before spinning. I also had excessive copper deposits with undersized jacketed. Even with over sized lead I don't shoot near maximum loads in high powered or leading occurs. Accuracy may be a problem with undersized bullets but lead or copper removal is the real problem for me. I have a .452 mold I'll never use because I later bought a .454 mold for my .452 diameter Colt. It made cleaning a lot easier. Ed.

 

[Jim Watson]

243wnxb,
Bear in mind that he does NOT have an Italian Mannlicher Carcano rifle. He has a Japanese Type I rifle in 6.5x50 Jap on a Carcano receiver. And, apparently, an Italian barrel with their oversize bore and a Jap chamber. Doesn't even have the protruding Mannlicher magazine for en-bloc clips, it is a flush Mauser type.
He's going to have to use 6.5x50 load data, with all usual starting load precautions.

 

[freakshow10mm]

Slug the bore, size to groove diameter or .001 over. Divide chamber pressure by 1422 and that is the optimum BHN (hardness) to provide complete obturation (seal off the bore from the gas). Softer will obturate, harder may not obturate and induce leading.

The best source for lead bullet casting and shooting is www.lasc.us. Click on "cast bullet notes". Read the articles.

 

[Cypress]

Thanks for the article link 243winxb. Good Info. This gun shot around a 3" group at 50 yds with some reloads I had bought that had .264 bullets. I'm curious now as to how much this will improve with the .268 bullets. If that doesn't work I'll have a good reason to tell my wife that I need to start casting my own.

 

[scrat]

Yep then you just need to find a mold. If that was my gun and i could not find the right bullets, for optimum accuracy. I would have one made. You may spend 50-100 for a mold. but you will be able to make thousands of thousands of bullets. Same time you will have the best accuracy money can buy.

 

[243winxb]

Bear in mind that he does NOT have an Italian Mannlicher Carcano rifle. He has a Japanese Type I rifle in 6.5x50 Jap on a Carcano receiver. And, apparently, an Italian barrel with their oversize bore and a Jap chamber. Doesn't even have the protruding Mannlicher magazine for en-bloc clips, it is a flush Mauser type.
He's going to have to use 6.5x50 load data, with all usual starting load precautions.

I said i was not an expert on the subject, thank you for the info. I had a 6.5 carcano #Y8424 many years ago with a groove dia. of .267" it shot ok/not great when loaded with jacketed .264" dia. bullets. I could not find my loading data that i used, but my Lyman #45 has data. There was an American Rifleman Reprint on Military Rifles that covered most of the common rifles, very usefull to me at times. I do know that jacketed bullets do NOT expand/obturate http://en.wikipedia.org/wiki/Obturate Take note at what pressures are needed for a bullet to obturate with different alloys/types/copper in the barrel to fill the bore. There will be gas blowby around the bullet with a .268" bullet in a .270" groove. IF YOU CAN BELIEVE ANYTHING YOU FIND ON THE INTERNET lol

 

[243winxb]

Cypress , yes i always had to see what a gun would do, had to shoot them. One last thing on cast bullets for rifles. Shooting 30-06 and 30-30 with groove dia. of .308". Cast bullet dia. i used was .311" with a gas check. Pistol bullets are sized to exact groove dia. or as close as possible on the + dia. side. Googled this- "The Type I rifles built by Italy for Japan under the terms of the Anti-Comintern pact from 1939-1943 are in standard 6.5x50 mm Japanese. Their Italian origin should not be taken to mean that these will safely fire the longer, but outwardly similar, 6.5x52mm Carcano round." http://en.wikipedia.org/wiki/6.5_mm_Arisaka History of firearms, very interesting, all most as much fun as shooting them.

 

[cracked butt]

There are a couple of different ways to skin this cat:

First of all do a chamber cast to determine the siz of the throat and how much bullet it can take. If it has a large throat, you might be able to get away with shooting a bullet dropped from a .277-278 mould meant for a .270 winchester so long as you can chamber it and the bullet will fit into the neck of a fired case. This sounds pretty unconventional, but if you use a mild load the barrel will act as your bullet sizer- this is commonly done with 8x56r mannlichers using a .338 cast bullet, I've done it myself.

You can also use a bullet dropped fromt he same mould and have Lee make a custom sizer- they charge about about $25 for them, and size the bullet down to .271-.272 or even a bit bigger. Once again, the size of yoru chamber and the inside diameter of the case neck will dictate how big you can go with it.

Another option would be to find a .268 mould for the carcano (good luck) and apply thin strips of aluminum tape around the cavity to open it up a bit- 1 layer of tape around the cavity will get you very close to where you need to be. The downside is that the bullet will have an oblong profile making it harder to install gaschecks. You can try a bullet like this without gaschecks, or take a large ball bearing ball, place the ball on the cup side of the gascheck, and tap it gently to open the GC up a bit so that it will fit. You'll still need a custom sizing die if you use a gascheck.


If you want to use jacketed bullets, just use the .268" carcano bullets, they should work justt fine. Many people shoot .264 bullets through swedish mausers with excellent accuracy without ever realizing that a Swedish mauser's groove diameter is much more likely to be between .265-.266" than to be .264". FWIW, I use a custom bullet mould for the swedes with driving bands getting progressively larger from .264-.267".

 

[Jim Watson]

I don't think cast bullet approaches are going to be much help on a jacketed bullet load.

Unless you wanted to look into paper patching. It has been done to paper patch jacketed bullets up to size.

 

[Cypress]

Ordered the bullets and dies today from Grafs so I guess I'm gonna find the sure answer to this one the interesting way. Thanks for all your help!!!